Mattress



FIG. 1 is a perspective view of a mattress showing our new design;

FIG. 2 is a top plan view thereof; and is also a bottom plan view of the mattress of FIG. 1;

FIG. 3 is a front elevation view thereof; and is also a rear elevation view of the mattress of FIG. 1;

FIG. 4 is a right side elevation view thereof; and is also a left side elevation view of the mattress of FIG. 1;

FIG. 5 is a detail view of a portion of FIG. 1 taken from detail section 5-5; and,

FIG. 6 is an enlarged fragmentary view of a portion of the corner of the mattress of FIG. 1.

In FIGS. 1, 5, and 6, the dot-dot-dash broken lines encircling a portion of the claimed design are illustrating a boundary of an enlarged detail view and form no part of the claimed design. 

CLAIM The ornamental design for a mattress, as shown and described. 